"There are some really quite dramatic changes in many areas as farmers abandon portions of the landscape, especially rice paddies that are small and inefficient," said Kevin Short, a professor of environmental education at the Tokyo University of Information Sciences (TUIS).

Since the 1960s an increasing percentage of ancient satoyama landscape has been transformed into golf courses, factories, and housing—threatening many species.

Conservation groups have been rallying to save satoyama, and a popular campaign featuring the titular forest spirit from the animated film My Neighbor Totoro has helped raise awareness.

"As farmers are becoming older, there are fewer young people coming to work the land," Short said, "so [aging farmers] are keen to reduce the amount of labor they need to put in."

Nature vs. Nurture

Literally translated, satoyama is a carefully managed border region between arable land and the mountains that represents development of the Japanese countryside over centuries of agricultural use.

Initially satoyama meant community-managed forests, with fallen leaves collected to use as fertilizer for the rice paddies and fallen branches or harvested trees taken for building, cooking, and heating.

The idea expanded over time to encompass mixed forests, rice paddies, irrigation ditches, grasslands, and small farms.

A typical satoyama might have stands of bamboo alternating with forests of oak and red pine, lined with farmers' houses and small fields of crops.

Mud-lined irrigation ditches and canals would support fish, water-dependent insects such as dragonflies and fireflies, and wading birds.

The the nonprofit Totoro Hometown Fund, founded in 1990, has done research showing a decline in satoyama within Japan's roughly 11.6 million acres (4.7 million hectares) of farmland, likely due to development projects that started in the 1960s.

Many mud-lined irrigation ditches, for example, were re-lined with concrete to allow water to move faster, TUIS's Short noted. The move made farming more efficient but had a huge impact on wetland wildlife.

In addition "small paddies are being consolidated into larger ones with drainage pipes that drain much faster and more effectively than in the past, meaning that [the paddies] no longer stay wet and muddy throughout the year," he said.

"If they cannot get water throughout the year, frogs and dragonflies that breed in these areas are unable to return and are becoming rarer, as are the larger species, such as herons and other birds, that feed on them in turn."

This summer, experts at Japan's Iwate University expressed concern that deterioration of satoyama habitat was affecting the migratory gray-faced buzzard, a hawk species listed as threatened by the Japanese environment ministry.

In 1982 some 54,000 of the buzzards were tallied as they migrated from Japan to Southeast Asia for the winter months. By the 1990s that figure had dropped to 20,000, and it now stands at just 15,000.

Cultural Heritage

In addition to farming modernization, a global economy means the Japanese are able to obtain food, fuel, and other items that satoyama used to provide for cheaper and in larger bulk from other sources.

Groves of oak once managed by local cooperatives, for instance, have been allowed to grow over as cheaper sources of wood are imported from China and Southeast Asia.

The oaks "have not so much faded away as been choked by no longer being tended," said C.W. Nicol, a environmental campaigner who has used his own money to preserve such a forest in Nagano Prefecture in northern Japan.

This return to nature can actually damage the region's biodiversity, some experts say, as thicker brush blocks the sunlight that allowed a wider range of plants and insects to thrive on the forest floor.

The Totoro fund has benefited from financial donations from across the country—proof that many in Japan want to see their cultural heritage remain intact, said Totoro Hometown spokesperson Mie Araki.

"There are still a lot environments where we can experience a rich natural environment, and our aim is to pass that on to future generations," she said.

TUIS's Short agrees that funds like the Totoro campaign have helped revive satoyama in some areas, but he warns Japan's current agricultural policies present an underlying problem for sustainable farming in general.

"The European Union gives farmers subsidies for engaging in environment-friendly agriculture," he noted. "But here they subsidize farmers who increase productivity [by any means necessary]."